Improvement in making steel castings without blow-holes



UNITE STATES PATENT OFFICE.

FERDINAND VALToN, on PAnrs, AND JULEs IJUVERTE AND ALEXANDRE POUROEL, orTERRE NOIRE, LOIRE,FR.ANGE, ASSIGNORS T0 ALEXANDER L. noLLuY, onBROOKLYN, NEW YORK.

IMPROVEMENT IN MAKING STEEL CASTINGS WITHOUT BLOW-HOLES.

Specification forming part of Letters Patent No.

214,210, dated April 8, 1879; application filed July '22, 1878; patentedin France, May 17, 1876.

To all whom it may concern:

Be it known that we, FERDINAND VALToN, of Paris, in the Republic ofFrance, and J ULEs Envnarn and ALEXANDRE PoURoEL, of Terre Noire, Loire,France, have invented new and useful Improvements in Processes of MakingSteel Castings Nithout Blow-Holes, of which in g carbon, in a mannertube-hereinafter fully described.

It has long been known that silicon tends to prevent the formation ofbloW-holesin steel castings. The theory of its action may be stated asfollows: Blow-holes are known to befilled with carbonic oxide,presumably produced by the reaction of the oxide of iron on the carbonpresent; but when silicon is present it decomposes thecarbonic oxide bytaking up its oxygen. The carbon set free is dissolved in the metal andthe silica is difl'used'throughout it. This silica combines'with iron,fornnng sllleate of iron, which, being but slightly fluid,rcmains in themetal, preventing its homogeneity and making it both red-short andcold-short. As the metal is more or less oxidized during itsmanufacture-for instance, in the Bessemer or in open hearthprocesses-the foregoing "reactions willaccordinglyyary more or less indegree, and consequently the product will vary in composition andquality, so that while the mere addition of silicon to the metal mayprevent blow-holes, the product will not be strong and uniform.

Our invention, which overcomes these difficulties, may be practiced ineither the open- .hearth furnace, the Bessemer converter, or thecrucible.

We will firstdcscribe the operation inthe open-hearth furnace. of threethings-first, the initial charge; second, the softening materials; and,third, the final additions.

charge is an ordinary spiegeleisen, for the folcon and manganese, whichhave a high ailinity for oxygen, and will take it out of oxide of iron.Therefore itis important to prevent, as far as possible, the formationof oxide of iron during the process, in order that it may not oxidizethe final additions and con the initial charge enough silicon ormanganese, or both, (preferably a large proportion of manganese,) tosatisfy the oxygen which is present durin g the process. We prefer tomake the initial charge of an ordinary spiegeleisen con taining from sixto twelve per cent. of manganese, and also containing silicon and carbonin the usual proportions; or this spiegeleisen may be replaced by onericher in manganese,

pig-iron containing silicon and carbon, in the 'usual proportions, 1nsufficient quantity to of manganese.

We sometimes make the initial charge of an ordinary pig containingsilicon and carbon, and afterward add the manganese in the form ofspiegeleisen or form-manganese; but we the charge of spiegeleisen, asbefore described. When the initial charge is Inelted,it then becomes theinitial bath, and the softening materials are added as in the ordinaryMartin practice. The selectionof these materialsdepends uponthe desiredgrade of the product. If a hard product is wanted, materials likesteel-scrap o'r Bessemer-rail ends should be used; but if a softer gradeis required, matebefore they are put into the bath; but they may becharged cold.

While the-operation is going on slag-tests are taken by dipping a bar ofiron into the The charge is made up The material most suitable for theinitial,

lowing reason The final additions contain silivert them into slag. W'etherefore provide in or byferro-manganese diluted with ordinaryleave inthe mixture the indicated proportion I have obtained the best resultsfrom making rials low in carbon, like wroughtriron scrap orcharcoal-blooms or puddled blooms, should he, employed. We prefer to.heat these materials bath. If the fracture of the film of slag ad heringto the bar presents an olive-green color, manganese is present insuflicient quantity to keep down oxidation. If, however, the slag isblack, or nearly so, spiegeleiscn, or, preferably, ferro-mangancse, mustbe added to the bath until the proper color is restored to the sla When,however, the softening materials are melted and the metal tests (to befurther described) show that the bath is ready for the final additions,thedark color of the slag should show that only a trace of manganese isleft in the bath. 1f either a large quantity of manganese or a largequantity of oxide of iron were in the bath at this stage, there would beno means of determining the required quantity of Y t he final additions;but when the bath is nearly free from both these substances the finaladditions can be added in the right quantity to perform their requiredfunctions. Metal tests are also taken dnrin g the operation, preferablyby casting a round ingot, about three inches in diameter and one andone-half inch thick,

. and hammering it, while still red-hot, into a disk about three-eighthsinch thick. .The disk is allowedto cool, and then bent cold. Then itbears hammering and an amount of bending proportionate to the degree ofhardness required in the product, (examples of which will be given,) thefinal additions should be made to the bath.

The final additions, which are disposed of as hereinafter described,give to the product that freedom from blow-holes and slag and thathomogeneity and density which impart the qualities desirable in steelcastings.

.In order to provide with certainty the necessary amount of the finaladditions, we have found it requisite to add them in excess of the am01111 ts theoretically required for thereactions hereinafter described,but at the sametiine in definite proportions. That portion of the finaladditions not'employed in these reactionsremains in the final product.

\(Ve have specified the manner in which silicon prevents blow-holes, andthe fact that after the addition of silicon a slag, chiefly of silicateof iron, remains mixedavith the bath. Manganese is added partly for thepurpose of freeing the metal from this slag. The theory of its actionmay be described as follows: In

the decomposition of carbonic oxide (which would form blow-holes) bysilicon, silica is produced, which combines with the iron, forming asilicate of iron. The manganese combines with thesilicate of iron,forming a very fusillfle slag, which rises to the surface of the bat- Apart of the manganese reduces any oxide of iron that there may be in thebath, and prevents the production of gas by the reaction'of this oxideon the carbon. I

The final additions essential are. silicon and manganese, whichweintroduce in the form of either a special compound of silicon, mangaanese,and iron containingcarbon,orasiliconized pigiron andferromanganese. ,A part of the impart an additional amount ofcarbon tothe product.

. The quantity of silicon and manganese to be added will be governed bythe required character of the product. The required silicon will be 0.20to 0.60 percent. For hard steels the manganese will be 0.50 to 1.60 percent.,

and for soft steels, from 0.20 to 1.20 per cent.

Many grades of hardness may be obtained conforinably with the varsilicon, manganese, and carbon.

We will now give several types of the final additions First, for hardsteel, when the test-disk bcfore described has no radial cracks on theedges above one or tw0 inches deep, and when it will bend cold until thefolds are about one Iron. 845.20 Carbon 3.20 Silicon .3.60 Manganese9.00

. I 100.00 which will represent a total additio to the cha'rge in thefurnace of-- Iron; 12.22 Carbon 0.46 Silicon 0. 52 Manganese 1.30

A part of the silicon and manganese will perform the reactions describedabove, while the rest will remain in the product, which will have aboutthe following composition Garbon 0.65 to0.70 Silicon 0.45to0.50Manganese 1.00to 1.30

()r we add eleven per cent. of a pig which has the followingcomposition:

and also two per cent. of ferro-ma-nganese which has the followingcomposition:

Iron 29.50,

Oarbon..... 5.50 Manganese 65.00

'which will represent a total addition to the charge in the furnace of-Iron 11.81

Carbon... 0.5L Silicon 0.55 Manganese.. 1.30

ying proportions of a result nearly identical withthc one obtained bythe first method.

Second.fom medium soft-sleel,when thetestdisk .is only rough on theedges, without deep cracks, and when it will bend cold into a close foldwithout cracking, we charge the final ailditions, which consist of sixper cent. (if a special pig, of the following composition:

Iron. 7l..l0 Uarbon 3.00 Silicoin. 7.00 lllanganesc. 18.00

representing alotal addition to the charge in the furnace of'- Iron. 428Carbon.. 0.22 Silicon. 0.42 Manganese. 1.08

Taking into account what may remain in the bath and the losses byreactions, the final product would contain about: I

Oarbon.. 0.27 to 0.32 Silicon J 0.35 to 0.38. Manganese 0.00 to 1.20 )rwe add six per eentof the following pig: Iron.... ......01.00

Carbon 3.10 Silioon....l... 5.00

. 100.00 representin g an addition oi -Iron-.. 5.51 Carbon 0.10

Silicon. ..i J 0.3

and also one and a half per cent. of ferro' manganese which has thefollowing composition:

Iron..; 24.50 Carbon 5.50 Manganese. 70.00 representing an additionofiron. 0.3

Cali- 011.... 0.08'

ll langanese. .05

The total additions willbe then:

Iron. 5.88 per cent. Carbon. 0.27 per cent. Silicon.. 0.30 per cent.Manganese. 1.05 per cent.

Taking into consideration the circum stances above mentioned, theproduct would contain about:

Carbon. 0.32am? Silicon........... 0.23 to 0.26 Manganese 0.00 to 1.20

In giving the above proportions of finaladditions, we of course do not-mean to restrict ourselves to the exact proportions given, but have.stated them as the formula from which we have obtained the best results.\Ve, how

ever, contemplate varying these proportions within such limits as may befound requisite by reason of the character of the charge in the furnacewhen the final additions are made. .Ve obtain the best results byheatingthese additional ingredients, so as not to cool the furnace justbefore castin When pig and term-manganese are used separately, the pigis preferably charged first, and when it is nearly all melted theferro-manganese is thrown in and the bath vigorously rabbled for aboutone minute. Casting should take place as soon as practicable after thefinal additions are well mixed, so as not to allow too great aproportion of the silicon and manganese to pass into the sla In usin our.jm movements in the Bessemer converter we make the initial chargeentirely of pig-iron containing manganese, or we put' wrought-iron orsteel-scrap into the converter along with the pig-iron or during theconversion.

'ln order to prevent the development of too great a heat by theoxidation of manganese earl y in the operation, we prefer to introduce apart of the manganese, which purifies the bath and ii ts it for theiiualadditions, as here inbei'ore fully explained, during the latter part ofthe process, so that it may be chiefly oxidized by the oxide of ironpresent rather than by the air blown into the converter.

Slag and metal tests should be taken (by.

turning down the converter) in the manner and for the purposeshereinbet'ore described. We find that itrequircs more care and skill totest and to secure that purification of the charge which tits it forreceiving the final additions, as hereinbefore fully explained, than arerequired in the open-hearth process first described; but equally, goodresults may be obtained.

The use of wrought-iron and steelscrap in the converter will prevent thegeneration of too great a heat in the converter. The proportions ofwrought-iron and steel-scrap, as well as of: manganese, in the chargemay b largely varied by one skilled in the art, ac-

cording to the principles hereinbefore ex-r plained. The chemicalfeatures of the converter process are very similar to thoseof theopen-hearth process. The important condition is that when the charge isblown it shall be as li.tle oxidized as possible. The final additionsare the same in composition and amount as those specified for the openhearth process. 7 H

-When the charge in the converter is shown by the slag and metal teststo be ready for the final addition they may be run into the converter orinto the ladle in a metal state; but I we pret'er to put them hot, butuumelted, into the converter. As soon as they are. well mixed i with thecharge casting should take place.

forth. The greater the oxidation of the baththe greater the amountofmanganese needed to purify the charge and to thus prepare it for thefinal additions. I

The manner in which we prefer to practice our process in the crucible isto take the ma terials already purified instead of puritying them in thecrucible. \Vc take wroughtrirojn or steel-scrap or blister-steel, as inthe ordinary crucible process. Then a very soft product is desired thecharge should be made of \vrought iron. XVhen a harder product is atsired a more carburized material should be i used.

The silicon and nianganestriare included in the charge when the crucibleis ,fillcd, all the materials being put iiitd it cold; or they are addedto the charge at any time before pouring; or they maybe put into theladle into which the crucibles are emptied 'hefore casting. \Ve preferto put the silicon and manganese into the crucible along with the chargeof wrought-iron or steel-scrap or similar ma- .terial. The purity ofsuch a material as com- T specified to one-third of that amount (if thematerials are Very pure and the oxidation very slight) will make aproduct of the hereinafter specified physical character, the criterionbeing the degree of hardness of the product, which those skilled in? theart can readily determine. I

The metal produced in the open-hearth fur- .nace, or in the Bessemerconverter, or in crucibles, may be cast either in cast-iron molds orelse in molds made of any suitable materials, such as fire-clay, sand,ground crucibles and tire-brick, &c.

The metal which we have obtained in the manner described above, whenproperly cast and annealed, has a specific gravity of 7.78 to 7 .91.ltcan' be rolled, hammered, forged,and welded without injury.

' In order to give it the strength of a forged or rolled steel withoutforging or rolling, this metal should be carefully annealed andcarefully cooled afterward. The time during which annealin g is to takeplace will Vary according [to the degree of hardness and the thicknessof the pieces to be annealed. i The average physical qualities ofmany-samgive below.

Elastic limit: 26.67 to 28.57; 15.87 to 19.68. Breaking strain: 53.97 to57 .15; 38.10 to 44.45. Elongation: 2.5 to 6 per cent. 1-3 to 20 percent.

inch.

'inanner described are about as follows:

Very hard steels: A batman... 0.70to

Very soft steels: I I g "Carbonunu dis-mono SlIlCOlI 0.10 to 0.25

Manganese 0.40 to 1.20

This metal can be used for most purposesin civil, military, and navalconstruction. I Having thus described the object and naknown to us ofpracticing the same, what we claim as new, and desire to secure byLetters Patent, is

1. The modchcrein described of treating a bath of inoltei'rliron formaking steel castings for the purpose of preventing unsoundness due tothe presence of blow-holes, slag, and other impurities in the castmetal, which mode consists in providing the initial bath with manganese,then putting in the scrap or other metal, and. finally adding to the'chargesilicon, manganese, and iron, the iron containing carbon,'and thesilicon and man ganese being in about the proportions specified,substantially as and for the purpose set forth.

2. The mode herein described of treating a bath of molten iron for making steel-castings to the presence of blow-holes, slag, and otherimpurities in the cast metal, which mode consists in adding to thecharge silicon, manganose, and iron, the iron containing carbon, and thesilicon and manganese being-in about the the purpose set forth.

,In testimony whereof we have signed our names tothis specification inthe presence of two subscribing witnesses.

FERDINAND VALTON. J. EUVEBTE.

ALEXANDRE POURGEL.

Ri CEARD- litiGR-INNELL.

ples of this metal, tested after annealing, we

, Weights given in tons (2,240 lbs.) per square- Tliepcrccntages ofcarbon, silicon, and manga'liese in the metal we have obtained in the-120 Silicon..'.....-.....,........... 0.50to0.60. 'ManganeseUQU,0.70to1.60

ture of our invention, and the best methods for the purpose ofpreventing unsoundness due proportions specified, substantially as andfor

